Field
Integrated circuits and more particularly, monolithic three-dimensional integrated circuits.
Description of Related Art
Monolithic integrated circuits (ICs) generally include a number of transistors, such as metal oxide semiconductor field effect transistors (MOSFETs) fabricated over a planar substrate, such as a silicon wafer. Lateral scaling of IC dimensions is becoming more difficult with MOSFETs gate dimensions now below 20 nm. As device sizes continue to decrease, there will come a point where it becomes impractical to continue standard planar scaling. This inflection point could be due to economics or physics, such as prohibitively high capacitance, or quantum-based variability. Stacking of devices in a third dimension, typically referred to as vertical scaling, or three-dimensional (3D) integration, is a promising path toward greater transistor density.